(this is Marios version)
I followed the recipe pretty closely, though I only made 1/2 recipe. Two lbs of meat total instead of four seemed just fine for my household. I also could not find the cheese he mentions, I used a soft provolone instead but I'm sure any semi soft cheese would work just fine. I wouldn't go with anything too sharp otherwise you might overwhelm the vegetables. I blanched the carrots as directed but didn't bother blanching the spinach or the scallions. All of those extra steps for the spinach just seemed like too much work.
One tip I would recommend, that made it much easier to work with, is lining your work surface with wax paper. Spread the flour and breadcrumb mixture on the paper and then when it's time to roll you can use the wax paper as a tool to help you get a nice tight wrapping. Otherwise I think it would be very hard to wrap up without tearing it over and over again.
I also didn't make the sauce, I used my stoneware pan and when I looked at what was left in the pan and it was mostly fat. It did not seem like it was going to make an appetizing sauce at all. I may not have used enough water in the pan, I didn't measure.
All in all this is a really delicious recipe that is a fun change from regular meatloaf and it looks really impressive as well.